When a high-school kid uses her own money to buy a hardcover book the day it appears in stores, a parent notices. When my nearly 18-year-old suggested that I read said book, I saw a rare invitation into the private world inside her head.

Not since the Harry Potter series have I seen that girl so engrossed in a book — walking, eating, fighting sleep just to read.

The book that enthralled Miranda more than any senior project or AP class was “The Wise Man’s Fear,” the second in “The Kingkiller Chronicles,” by Patrick Rothfuss. The first in the three-part series, “The Name of the Wind,” came out in 2007 and became a best seller, the second in March 2011 (and in paperback from publisher DAW Tuesday), and Rothfuss is working on the third.

Central to both novels lies The University, where our hero Kvothe finds not all professors have the students’ best interests at heart, and not all things worth knowing are found within library walls.

Rothfuss followed the old “write what you know” advice, creating a world that combines his love of fantasy fiction, interest in role-playing games and nine years as a college student in Wisconsin (where he wrote a humor column for the school paper) and two more in Washington.

Best-seller status aside, among teenagers, word of mouth counts for more than any list. Back when Miranda’s astrophysics-studying friend handed her his own paperback copy, pages velvety from multiple readings, it was one of those “you have to read this” moments.

When she said, “Mom, you should really read this book, I think you’d like it,” it was another of those moments.

So the chance to interview the author made both mother and daughter a little nervous and star-struck.

In other interviews, Rothfuss seemed like funny, foul-mouthed college newspaper columnist he once was. I was ready with a list of questions about the writing process, the nature of fame, etc. Advice for my daughter was not on the list.

But when a perennial college student-turned-best-selling author offers freshman-year counsel to a fan, the student and the parent pay attention.

Rothfuss: I’ll tell you this, as somebody who was a student for a very long time, and also a teacher, at some point during your freshman year, something will happen, and it’s different for everybody. For some people it’s a series of events that all add up, for some people a grandparent dies or a childhood pet dies, or your roommate is an absolute monster, or you get your first B, or your boyfriend turns out to be a jerk, or you realize you don’t want a boyfriend, you want a girlfriend.

When that happens it’s going to seem like the absolute end of the world. Seventy five to 80 percent of the student body goes through this and it’s magnified to this huge degree because you’re away from home, away from your traditional network of support.

I want you to know it’s not as bad as it feels — don’t get me wrong, it will suck — but, this too shall pass. Don’t try to choke it down and be a cowboy and take care of it all to yourself. Call people you trust, it might be your parents, it might be a friend.

I’ve known a lot of students who drop off the world for three weeks and re-emerge in my class and say ‘things are awful, what can we do?’ When things are awful and you can’t hold it together, go and talk to your teachers. They can’t work with you if all you do is disappear.”

Miranda: Okaaay, thanks.

Rothfuss: Now Mom, here’s the advice you don’t want me to give her. You’ve got a great chance in college to do all sorts of terrible irresponsible things, and you should totally do them. I mean, make huge mistakes. This is the time in your life if you screw up, it’s okay because you can bounce back from it.

I’m coming up on 40 and there are some things that if I make mistakes now, people will look at me and say, what is wrong with you? But if you do them in college, they’ll say ‘ah reckless youth, what a learning experience you just had.’

The key is making the mistakes that you’ll learn something from and have great stories to tell for the rest of your life, but being able to make a few intelligent choices in terms of the potential consequences. Getting a ticket or breaking your arm is not a terrible thing that’s going to haunt you for the rest of your life. There’s a big difference between breaking your arm and let’s say, getting herpes. One sucks and the other is a permanent issue and that’s as much as I’m going to say on the topic.

(From there, we moved on to more traditional author-interview subjects.)

Q: Did you ever think about not finishing the books, just sticking with the column and teaching gig?

A: Sure, that happens to anybody who writes any long project. I took it seriously and devoted time to it but that’s no different than any sort of hobby. We all know people who put thousands of hours into their model trains or their stamp collections or their gardens. I would get sick of it and stop writing for a couple of months or half a year.

The nice thing about a hobby is that you’re doing it because you want to. The mentality of the hobby is you never get halfway through your model railroad and think ‘ga, I’m never going to sell this for a million dollars and get famous.’ Just like anything you love, you can get heartily sick of it, but you usually come back.

Q: So the book was your hobby, now what is it?

A: Now it’s my job. And that took a lot of adjustments. Now my hobby is my fund-raiser, Worldbuilders. (It raises money for Heifer International through auctions of hard-to-find fantasy books.

Q:One of your main themes is fame, and how reputations are forged. Does it seem ironic that you are dealing with fame of your own?

A: (Laughs.) Probably the fact that I’m able to maintain any semblance of my cool through this whole process is I used to write a humor column for the local campus paper. I got to experience celebrity in a very small microcosm, it was almost like getting vaccinated. It’s profoundly disorienting to go from zero to celebrity.

Q: But fame is something that people seem to crave now. Did you?

A: I probably did crave it when I was younger. When I think of fame, I think of that old video clip of Beatles where the girl’s screaming and crying. When you’re 18 years old, you look at that and wish ‘I totally wish someone would feel like that about me.’ Maybe if I were 23 years old, I’d be riding this like a rock star, but maybe it’s because I’m from the Midwest, it is past the point where I’m entirely comfortable with it.

I never set out to become ‘famous.’ I mean, when you’re 14 you think ‘I’m gonna become a writer and people will want my autograph and that’ll be cool,’ but you grow up and you learn that’s just not how the world works. I resigned myself to the fact that I would probably never be published and if I did it probably wouldn’t be a big deal. Then I really did get lucky and did kind of get the deluxe package of fame and money.

Q: Since you brought it up, did you make a lot of money?

A: I did get to quit my day job, which is more impressive than it sounds if you didn’t know that I was a half-time assistant lecturer at the local university. I was walking away from like $15,000 a year there. Lately, with the sale of the second book, I’m having to deal with money on a different level.

Q: You once said the books were a kind of satire. What did you mean?

A: It’s more an issue of ‘nobody picks on my little brother but me.’ I can satirize fantasy because I love fantasy and I know it very well. Creating a fully realized world yet having fun with the genre was the hardest thing in these books.

When I heard Peter S. Beagle say “The Last Unicorn” was the most excruciating book he’d ever written, that it was a fairy tale that was also a satire of fairy tales, I thought ‘that’s what I’m doing.’

It is heroic fantasy but it’s also making fun of the conventions of heroic fantasy that have gotten a little tired. I didn’t want this to be a book that could only be enjoyed by people who have read a thousand fantasy novels. I wanted it to be read in its own right.

Q: Do you have an end?

A: Oh yeah.

Q: How did you break the manuscript into separate books?

A: I had to figure that out before I got an editor. You can’t just go ‘Here’s something that’s longer than the Bible.’ You want to be able to say here’s a book that stands on its own but is the first of a trilogy. I had already picked an ending place and I had to make sure the first book felt satisfying without doing anything artificial to fake an ending.

Q: Will there be more than three books?

A: This story will be three books. I said that from the beginning and I’m sticking to it. That said, there are more stories in this world.

Q: What else are you working on?

A: A role-playing game, but that won’t come out till after the third book.

Q: What about a movie?

A: I’ve made a very integrated story that does make it very hard. I’ve been talking to a screenwriter but the problem is, how do you end the first movie? Harry Potter is great, if formulaic, because Harry beats up Voldemort at the end of every book. In mine, there’s no big sword fight at the end, so how do you pitch that to a bunch of Hollywood executives?